Environmental factors play a significant role in the causation of human disease. Thus, such disease is preventable to the extent that such factors can be identified and either removed from the environment or counteracted. Recognition of this possibility requires intensified efforts to identify the causal factors, to elucidate their mechanisms of action and to formulate appropriate measures for blocking or reversing their effects. The purpose of this Program is to provide training to prepare scientists for active and productive careers in environmental toxicology, with emphases on respiratory, molecular and genetic toxicology. The objective is to prepare the trainees to plan, conduct and interpret toxicological studies which are appropriate to specific scientific issues in question. The scope is broad, and trainees may, for example, be provided with backgrounds enabling them to examine mechanisms of environmentally-related disease as well as to improve exposure technology and methods of assessing biological responses. The Program provides for four predoctoral and two postdoctoral (Ph.D.) positions.